To pack a molded catalyst or a supported catalyst in a fixed bed reactor, it is common to employ a packing method wherein the catalyst is dropped from an upper portion of the reactor. In such a method, the catalyst may be pulverized or disintegrated by the physical impact at the time of the dropping. This tendency is distinct especially in the case of a molded catalyst or a supported catalyst which does not have high mechanical strength. The following may be mentioned as methods for suppressing such pulverization or disintegration of the catalyst at the time of packing.
In a case where a catalyst is to be packed in a reactor by dropping it from an upper portion of the reactor, a method is known wherein strings having a shape and a size substantially not to hinder the dropping of the catalyst, are provided in the reactor (Patent Document 1). Further, when a solid catalyst is to be packed in a reaction tube installed in a reactor by dropping the catalyst from an upper portion of the reaction tube, a method is known wherein a liquid is firstly filled in the reaction tube, then the solid catalyst is packed, and thereafter, the liquid is removed from the reaction tube (Patent Document 2). Further, as another method, a method is known wherein prior to packing a solid catalyst by dropping it into a reaction tube of a reactor, dry ice is packed in the reaction tube, then the catalyst is packed, and then, dry ice is removed by evaporation (Patent Document 3).                Patent Document 1: JP-A-5-31351        Patent Document 2: JP-A-9-141084        Patent Document 3: JP-A-10-277381        